As a big reader of horror stories, I find a sudden change in view angles very effective in building a feeling of weirdness. Fish-eye perspective for example, or unstable horizon when everything seemed pretty normal before. Or an angle that always keeps something hiding (for example a character we can't see the face, but everything around and how people react) that makes you crave to see better, and build anticipation, even if basically, you know more or less what you'll see.
As for pure terror, nothing works like turbomedia inserted in a comic. When you're so used to the static pannels, having a sudden movement or sound is just the worst nightmare @____@
But as a fellow comic artist, I must admit I wouldn't know how to do that sort of thing. Maybe ther's a special software ?
EDIT : Ow, sorry, I thought you were making a comic !
I'm also a huge reader of horror novels, but I did not analyze enough my reading to be able to give any advice... But I rarely feel pure terror or intense fear when reading.
More when I read short stories than long novels, that's for sure, as tension is easier to build in a short span of time.